It does click, so dont think its the idle switch. General driving is strange too, sometimes louder and more boomy than others.Tried driving it with the blue temp sensor disconnected. exhaust was even louder and boomy, so proof i suppose that a knackered sensor makes the exhaust louder, but not of a completely knackered sensor in my case, unless its half knackered!
ill report back if i ever find out what the problem is...